Picture: TASS/GETTY IMAGES/MIKHAIL TERESHCHENKO
Picture: TASS/GETTY IMAGES/MIKHAIL TERESHCHENKO

SA is currently not in a Covid-19 crisis. That is not to say people are not still dying. Over the past two weeks we have seen a daily average of 73 deaths attributed to the virus (officially). Rather, it is to say the current number of deaths does not represent a singular and unique cause of death, distinct from all others.

On average this country sees 78 daily deaths from tuberculosis (TB), 69 from diabetes and 140 from unnatural causes (vehicle accidents, homicides and so on). Each and every death is undoubtedly a tragedy, and something we must do our utmost to prevent. However, it would seem somewhat hypocritical — and perhaps even discriminatory — to remain in lockdown (albeit only at level 1) and impose extremely stringent social distancing requirements in fear of Covid-19, when similar actions are not taken in response to TB, for example.

So why are we still in lockdown? Why is my three-year-old daughter required to wear a mask to school and forbidden from hugging her teacher? The answer is that we fear the pandemic will worsen anew. In a word, we are afraid of a “second wave”.

Therefore, the most pressing question with which policymakers must be concerned is whether we are indeed likely to experience a second wave of the virus. Alternatively, as we fervently hope, Covid-19 deaths will remain stable or continue to decline.

To try to answer this question SA has the distinct advantage of hindsight over other countries that started experiencing the pandemic 10 to 15 weeks before we did. So let us study the behaviour of countries whose virus progression is mirrored by SA’s. Have these countries suffered a second wave?

To assess this, we need to establish a measure of the severity of Covid-19 that is both consistent and objective. The first candidate, and a favourite of the media, is the number of new Covid-19 infections (it appears that infections and cases are now treated synonymously, despite being two distinct concepts).

However, this measure is in truth totally meaningless without providing context, for the number of recorded infections is a function of the number of tests performed. A child who comes home and excitedly tells his parents he got six marks on his geography test will immediately be asked “out of what?” Six out of six, 10 or 100 will be met with very different responses.

A better measure would be the proportion of positive tests. However, this is not a consistent indicator. In different countries, and indeed at different times, the make-up of people being tested differs greatly. People are driven to take tests based on the climate of fear surrounding the virus, the current thinking of medical practitioners, the insistence of political and social leaders, the affordability of the tests and the actual availability of tests. Consequently, the demographics of the people being tested lack consistency among countries or even within a country over different periods. In other words, not only is the sample not representative of the population, but its representativity is inconsistent.

The number of ascribed daily/weekly Covid-19 deaths is a better measure. However, while it may be more consistent, it is not an objective measure. How does one determine with certainty whether a person died from Covid-19 or with Covid-19? Moreover, in SA, it is widely acknowledged that the official Covid-19 deaths are understated, as not every death is tested for Covid-19. The excellent research done by the SA Medical Research Council seems to indicate that actual Covid-19 deaths could be as much as twice the official number.

The best indicator by far is the total number of all-cause weekly deaths in a country. This measure is both consistent and objective. Subtracting the expected number of deaths from the actual number of deaths in a given week results in the number of excess deaths in that week. Expected deaths are estimated using simple projections or averages based on the deaths in recent years — in the ordinary course of events, deaths are remarkably stable year on year. The percentage of excess deaths in a country provides an excellent measure to assess the progression of a pandemic and allow its comparability between locations.

Excess deaths in SA since the beginning of April as a percentage of total mortality reveals a large “hump” representing a significant increase in observed mortality in 2020 when compared to similar periods in previous years. But just as shocking as the steep increase in mortality is the steep decrease that followed the peak. As of mid-September SA is no longer experiencing any excess mortality.

Not all countries have followed this progression. However, the majority of countries that were severely affected have followed the same path. These countries, which also experienced a large hump followed by excess deaths decreasing to zero or below, provide a blueprint as to what SA should expect in the coming months.

The progression of the pandemic in a few matching European countries (unfortunately, weekly mortality data is only publicly available for about 30 countries) speaks for itself: not one of these countries has experienced a second wave. This is not cherry-picking either. Not one country (where data is available) that experienced a large and sustained first wave, as did SA, has yet experienced a second wave.

Note that this includes Britain and Spain. The media have been bemoaning the terrible reappearance of Covid-19 in these countries, but the numbers do not agree. The cries are simply incorrect and ignore the facts. All of the countries examined have had a range of lockdown and social-distancing requirements — and a range of adherence to these. Nevertheless, there is not one country that has experienced another sustained wave of excess deaths.

These are the facts. I have not used any sophisticated or complicated models. I have made only small and largely inconsequential assumptions and presented the data as it is. As to the conclusions and policy implications, I make no comment. I trust that rational and logical readers will see the implications as self-evident.

• Freidus, a fellow of the Actuarial Society of SA, is founder of Five2two Actuaries.

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